Dennis F. Jones
Defence Res. Establishment Atlantic, Dartmouth, NS B2Y 3Z7, Canada
About 65 years ago the first flextensional transducers for aeroacoustic applications were constructed and tested by naval researchers. This first period of flextensional transducer development spanned the late 1920s to mid 1930s. Twenty years later, research on flextensional transducers for the generation of low-frequency underwater sound began. This second period of development extended from the mid 1950s into the late 1970s. A third period of flextensional transducer development began in the early 1980s when advances in acoustic quieting of submarines caused a renewed interest in low-frequency active sonar systems. This third period continues today. In successive periods there were an increasing number of countries, laboratories, industries, universities, and researchers contributing to the development of the flextensional transducer. All periods, however, were driven by naval requirements. Also, in each period there were technical advances and discoveries in many areas that influenced the evolution of the flextensional transducer. The purpose of this paper is to review the evolution of the flextensional transducer by focusing on the discoveries, advances, and motivations that distinguished the three development periods. In addition, new ideas for the future of the flextensional projector will be discussed.